The term "--39-LINK--39-" seems to refer to a specific connection, interface, or possibly a jumper on the board. In electronics, such codes are often used to identify particular connectors, test points, or switches. The "39" could denote a specific pin, connection point, or it might be part of a coding system used by the manufacturer or repair technicians.
The is a vital asset for anyone repairing Acer Aspire 5742/7742 series laptops.